The present invention relates to a light source unit for an optical apparatus.
Some conventional light source units for endoscopes are provided with a light controller for controlling a brightness of a light source. Therefore, it is possible to control the light source so as to provide a desired brightness when an objective portion is observed. In the light source unit of this type, after a power switch for the light source is turned on and the light source is set to provide a proper light intensity, the light beam is ceaselessly projected in a condensed manner from the light source into a light guide of an endoscope both in an observing mode and a non-observing mode. Because of this continuous condensation, the temperature of the light incident face of the light guide rises. In an extreme case, the light incident face is burned and damaged. Such an accident is more likely to occur as a luminance brightness of the light source is larger and a closed time of the light source switch is longer.
Also in a light source unit for an optical microscope, when a sample is continuously illuminated for a long time, the sample is changed in nature. Further, while texture emitting fluorescent rays are observed, the fluorescence tends to fade. A measure which has been taken to solve the problem, is to turn on the light source switch only at the time of the sample observation or to manually release a shutter provided in an optical path of the light source. The switch or the shutter operation, however, is troublesome for an operator and frequently disturbs him in the observation.
Accordingly, an object of the present invention is to provide a light source unit for an optical apparatus in which a light source unit illuminates a specific area only when the area is observed by the apparatus.
Another object of the present invention is to provide a light source unit for an optical apparatus which is easily operable.